text: Nyctalopia - Wikipedia  Nyctalopia /nktlopi also called night-blindness, is a condition making it difficult or impossible to see in relatively low light. It is a symptom of several eye diseases. Night blindness may exist from birth, or be caused by injury or malnutrition (for example, a lack of vitamin A). ... Another cause of night blindness is a deficiency of retinol, or vitamin A, found...